Sliding

I did some research and I've found out that stock shock towers
could be damaged with coilovers installed.
What would be the best way to reinforce shock towers?
Have anybody done this? Pics?

bogus

What year is your vette?

The later ones do not have this problem... it's only the earliest models, as I understand it.

If you want to reinforce, the front is where the problem is, and the fix is to weld more metal on them.

rocco16

Neither the upper shock mounts nor the suspension components (lower shock mounts) are designed to support the weight of the car or to take the loads that coilovers will place on them. From an engineering standpoint, bolting on coilovers is not a good idea.

That said, several CF members report many thousands of miles with no issues from their coilovers.

If you are set on putting coilovers on your C4, at least you are concerned about some of the strength issues. Good for you.
Take a hard look at the rear, lower mount especially. That alone scares me.

Larry
code5coupe

redrose

c/o are a great idea on race cars, equally not great for street....you may impress the ricers with c/o's on your stock street car, but anyone that really knows will smile and walk away

Coupe89

4 years running them. No problems here. I'm using DRM type.

rickneworleansla

Whats wrong with running them on the street? Will coil overs allow me to lower my car as well as improve handling? That would be my two biggest reasons for adding them. No re-enforcement's needed for 95 convertibles?? If I did decide to go to coil overs I would probably go with thicker sway bars also and change out all the bushings for poly. Who makes thicker hollow/tubular bars? Sorry for all the questions but its how we learn.

Thanks

rocco16

There are other, cheaper, ways of lowering your C4.
Will coilovers improve your car's handling? I ask...how will they do that?

They WILL, most likely, provide a quality shock....but you can get that with a set of standard Koni or QA-1's....you don't need coilovers to get a good shock. Will they reduce unsprung weight? Not enough to matter, if they do at all.

Coilovers are great for race/track use, where you can quickly and easily lower/rake/add stagger to match a particular track....and where you can re-align the suspension settings after each change.

On the street: they are not only not needed, they are not desireable....from an engineering standpoint. If you want the race look, well, they are hard to beat for visual impact...as long as the car is stopped and the hood is up or the wheels are off the car. See what I mean? ....their biggest feature only comes into play when the car is not moving. Where is the dynamic advantage on a street car?

Good luck with your decision.

Larry
code5coupe

redrose

what's wrong for street ? ....too much to list, but just for starters, look at the pics of coupe89's set-up above....notice the small hole in the upper cone on the spring--reason the hole is there: ''should'' have a nylon tie-wrap (some designs use a 'hairpin') holding the cone in place so that unusally long suspension excursions (which do happen) will not allow the cone move off-center , resulting in change of operating length , or on some types even allow the cone to depart; even with ties the cones occasionaly wander away......notice the lower adjusting nut (ring)--there are threaded holes for set screws to lock the ring at the selected level, but if you use set screws the threads on the adjustment collar are flattened and the ring won't turn; no setscrews and the setting will change during use (ok, no problem if you scale your car every time you use it like racers do)....notice the steel spring ends in contact with aluminum retainers--over time the aluminum is chewed away ....notice how the upper mount rubber bushing has been flattened by constant load--spherical ball mounts (other common type but more $) dont do that but need daily spray of lubricant, both types need frequent replacement.
i play with several types of race-only cars and we are forced to put up with the headaches to gain adjustability, if you like headaches jump in

1991Z07

Well...lets see....

Beside eliminating cross-talk of the mono-leaf, you can lower the CG pretty significantly with coil-overs.

I've seen quite a few running coil-overs for MANY thousands of miles with ZERO issues. I've had spherical rod-ends on my car for over 30k miles and don't need to lube them daily. They get greased about every 2-3 months, and they are just as tight as they were when I installed them.

Yes...they were developed for racing...but just about EVERYTHING on your C4 was...it was how they improved the breed. The coil-overs give you infinite adjustability, essential for racing on different tracks over the year. Not essential on the street, but it WILL improve the handling.

The "cheaper" ways have been shown to lead to failure of the monoleaf when the nylon "wedges" move over time and the frame files through the leaf spring...should give you a warm & fuzzy feeling when going down the road.

Pay attention to the details, and there isn't a problem. Bury your head in the sand and expect failure. With regular general maintenance, you should be fine. Take some precautions and reinforce the upper front towers and you'll be fine (although MANY have never done this and no failures).

MY 2 cents...

Sliding

How did you clear the sway bar? Did you move it forward or did using
of sway bar links on your pics make more space?

CentralCoaster

I was thinking about the shock mounts... and when the spring compresses quickly, the shock is absorbing a ton of spring force, and the shock tower sees that load, which could be 75% or so of the spring load when using a stiff shock.

It seems like the shock tower is already much more heavily loaded than we think.


Also, please explain the "cross-talk" of the fiberglass spring, why it's undesireable, and how this is any different than crosstalk from a swaybar.

Coupe89

I moved the sway bar up .75"

rickneworleansla

hmm.. I have a lot more info to go on now. It wouldnt be a problem to check adjustments and lube every three months, when I change my oil. I'm sure my street driving is a lot less harsh than track time. I've heard about some of the problems others have had with the lowering kits. The biggest install problem I would have is finding someone to re-enforce the towers. I'm guessing you would just weld in a little extra metal for support there. I still have plenty of time to think about it though. I noticed vette products sells an extreme touring suspension. Has anyone had any experience with this? It only says that the front is adjustable though.
http://www.vbandp.com/detail.aspx?ID=575
Doug Rip M sells an auto cross for $1k and the Xtreme grip with coil overs for $2k. What about these? Again I still like the ability to adjust heigth.
Exotic muscle would have to be bought in pieces but the coil overs are under $1k. Any comments on those?
Are there any others out there I should look at?

Thanks guys great info here.

redrose

your train of thought on shock mounts is dead on--many chassis builders don't think about this but wonder why their cantilevered mounts keep falling off midway thru a race....a modern shock absorber is really nothing more than a hydraulic cylinder with no external piping and a controlled internal leak to allow the length to change (make the internal leak adjustable and get $500 per shock)--since the fluid flow thru the leak is throttled, a very rapid loading of the shock may indeed produce mount loads as tho the shock was a solid bar, in fact-due to to inertia the load may be several times the vehicle weight.
cross-talk of the spring is produced by the pivoting action at the two mounting points (the rear, with only one center mount does not cross-talk, unless you have the VB&P rear spring mod/two mount)...x-talk decreases the downward spring force on the inside wheel while cornering....it is HIGHLY desireable, a suspension designers dream come true... much of what x-talk produces is the same as anti-roll (sway) action,only better.

CentralCoaster

What about uneven loading from the coil, and maybe even sideloading and deflection of the shock body? And how is there any weight advantage whatsoever?


The ONLY advantage I see is adjustability.


I'm putting them right up there with drilled rotors.

rocco16

A street car could go its entire life without seeing these type of loads, and the design engineers take this into account. Not many of us run into curbs at 90degrees/40mph. If we do, other suspension bits will fail before the shock mounts. As Coaster pointed out, the front upper mounts are pretty beefy. But what about the front lower arms? The rear upper mounts? The rear lower mounts? each one looks increasingly less able to withstand the stresses that coilovers will place on them.

Are you saying that dispensing with the stock transverse leaf spring is a step backwards? If I read your comments right, the coilovers would not be as desirable as the leaf spring.

Larry
code5coupe

redrose

i wish we had cal roads here, i'd slam the car to 1''g c with no springs and luv it (i guess some there do it)....don't need a curb to rip apart the suspension here, i've seen it done by potholes (and potheads), by railroad crossings, and by 4x4 wood that crawled onto the road.

yes, i do feel changing to c/o would be a step back...i have the springs, shocks, hardware and all necessary tools in my shop thanx to circle track racing, but c/o for the street?-never....if we had the budget and personnel, i would change to transverse fiberglass on the racers

bogus

say what?

The corvette is the ONLY performance car made today that does NOT have coil overs. It's the weakest part of the chassis.

we confuse the meaning of coil over, it's any shock/spring that is integrated. Hense, the average strut suspension of your average honda is a coil over. It's just been perverted to mean something more than it really is.

CentralCoaster

You keep saying it sucks over and over, but don't say why. Why are the corvette springs so bad Bogus?

I wanted to try leaf springs on our SAE formula car in college. The rest of the team rolled their eyes or laughed, but not a single one could give me a reason.

The leaf springs are difficult to package, and they can't be used unless they are designed around from the start. For most cars, it wouldn't even be a possibility. I'm also going to exclude all FWD cars from the performance category.

Macpherson struts are used because they are simple and cheap. They also perform cheaply.

The Corvette springs also allow for a lower hood line and don't load up the sides of the chassis as much, so not as much lateral support is needed at the uprights.

bill mcdonald

Have you done coil overs on a C4 Corvette?